1. Technical Field of the Invention
The present invention relates generally to an optical character reader designed to read characters handwritten or stamped in character entry frames printed on a medium, and more particularly to an optical character reader designed to extract character images from an optically captured medium image accurately even if characters are stuck to character entry frames.
2. Background of Related Art
Optical character readers are known in the art which recognize characters handwritten or stamped on a medium such as a document. Typically, such readers isolate and extract images of characters written in character entry frames printed on a document from an optically captured document image for recognition of the characters. Therefore, in a case where the character entry frames are printed with non-dropout color, it is necessary to fill in character entry frames so that characters are not in contact with or do not partially jut out of the frames because the frames printed with the non-dropout color will be captured optically together with the characters unlike those printed with dropout color. The simple extraction of characters partially jutting out of frames, thus, leads to errors in character recognition. The removal of unwanted frame images from captured character images on the other hand results in a lack of the character images, precluding accurate character recognition.
Japanese Patent First Publication No. 3-282895 discloses an optical character reader which is designed to remove portions of character entry frames not overlapping with characters to extract only the characters accurately. This system, however, requires fine analysis of locations of the character entry frames printed on a medium, leading to complexity of logical analysis of medium images captured by an image sensor.